They said the constitution provides immunity for Mr Trump from being sued in state court while he is president.

The lawyers said their position is supported by a long line of US Supreme Court cases requiring courts to show deference to the president and his schedule.

Former 'The Apprentice' contestant sues Donald Trump for defamation

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Ms Zervos was a contestant on Mr Trump's reality show in 2006.

She sued after Mr Trump dismissed her claims as "fabricated and made up". Ms Zervos claimed at a news conference in October that Mr Trump had made unwanted sexual contact with her at a hotel in Beverly Hills in 2007.

The lawsuit sought an apology and damages of $2,914.

Mr Trump's lawyers said he denied "these unfounded accusations" and was prepared to show that they were "false, legally insufficient and made in a transparent politically-motivated attack."

They said the allegations were even disputed by a member of Ms Zervos's family.

After appearing on Mr Trump's show, Ms Zervos said she later asked him for a job. She said they met and he kissed her on the lips and asked for her phone number. She said that during a later meeting at a hotel in California he became sexually aggressive, kissing her and touching her breasts.

Gloria Allred, the lawyer acting for Ms Zervos, said she did not believe that the president had legal immunity from a defamation lawsuit.

She said that the Supreme Court had addressed the legal immunity issue in a case involving Bill Clinton and "determined unanimously that no man is above the law, and that includes the president of the United States."